The present invention relates to the field of nutritional supplements and, more particularly, to a composition comprising an extract of saw palmetto berries and a method for the extraction of saw palmetto berry components.
Saw Palmetto (Serenoa repens) is a shrubby palm that grows only in the southeastern United States, and is most prolific on pine flatwoods in peninsular Florida and southern Georgia. The saw palmetto grows a seed stalk (spadix) in late spring, which flowers and then develops a hard green fruit about the size of a small olive. The fruit ripens in the summer, turning shades of yellow, orange and black. The ripe fruit is then harvested by hand during the late summer and early fall. Typical yields in harvestable areas range from a low of 200 lbs. to more than 1000 lbs. of berries per acre.
Saw palmetto berries have been ingested by Native Americans for many centuries. Early in the 20th century, naturopathic physicians in the U.S. began prescribing a tea made from saw palmetto berries as a mild diuretic and for genitourinary problems. It became a popular male tonic, but eventually the therapeutic value of the tea (a water extract) came into question and in the early 1940""s it lost both its popularity and its inclusion in the National Formulary. Research in Europe in the 1960""s led to the identification of the lipid portion of the berry and its medically active components, including free fatty acids and sterols, also referred to in the art as phytosterols, since they originate in plant tissue.
The therapeutic use of herbs has long been very popular in Europe, but is a relatively recent phenomenon in the U.S. It is instructive, therefore, to review the European experience with herbal medicines over the past few decades. In 1976, Germany defined herbal formulations in the same manner as other drugs, and today about 80% of physicians in general practice prescribe thousands of registered herbal remedies, with most purchases paid for by government health insurance. Other countries within the European Economic Community have similar requirements and restrictions on the manufacture and sale of herbal products, including saw palmetto, with the exception of the United Kingdom (U.K.) and Netherlands, wherein it is treated as a dietary supplement, as in the U.S.
A recent review article in the Journal of American Medical Association (JAMA, November 1998), summarized existing medical evidence regarding the efficacy and safety of saw palmetto berry extract in the treatment of BPH. The study analyzed the results of 18 controlled trials involving 2939 European men between 1965 and 1997. The review concluded that saw palmetto produced a marked reduction in symptoms of BPH when compared to a placebo, and the difference between saw palmetto and the prescription drug finasteride was statistically insignificant. The report further indicated that saw palmetto treatment produced a modest improvement in sexual function, whereas a deterioration was reported with the prescription drug. Also reported was the finding that saw palmetto extract produced fewer adverse side effects, and that its cost of from $3 to $17 per month compared favorably with approximately $67 per month for finasteride.
In 1978 the German Federal Health Agency (now called the Federal Institute for Drugs and Medical Devices), established an expert commission to evaluate the safety and efficacy of herbal remedies, termed phytomedicines (from Greek phyton, plant). This German Commission E actively checks and verifies data on thousands of registered herbal preparations to evaluate their credible utility. Such data include clinical trials, field studies, clinical cases, scientific literature, and medical association experiences. The evaluation process results in the establishment of xe2x80x9creasonable certaintyxe2x80x9d of the safety and efficacy of the herb being evaluated. The German standard is not equivalent to the standard of xe2x80x9cabsolute certaintyxe2x80x9d required by the US Food and Drug Administration (FDA) for drugs. The German approach, however, is much less costly and time consuming than the estimated $500 million expenditure and 12 years of research required to prove the safety and efficacy of a new drug for entry into the U.S. market. In contrast with the U.S., German authorities seem to believe that a reasonable certainty of safety and efficacy is adequate for remedies which have been long-used.
When the German Commission E completes an evaluation, a monograph is prepared for each herbal, with a positive or negative assessment regarding suitability for medicinal use. These monographs now totaling about 300, are published in the Bundesanzeiger (Federal Gazette). The monographs describe constituents, range of application, side effects, dosage, use and action of the herb. This listing represents the most accurate information available on the safety and efficacy of herbal medicines. They have recently been translated into English (Blumenthal, 1998).
In the U.K., statutory recognition of herbal remedies increased substantially in 1968 with passage of the Medicines Act. During the 1980""s, all U.K. manufacturers were required to make a thorough technical appraisal of their products and to provide evidence on quality, safety and efficacy to the National Department of Health. From a regulatory perspective, however, herbs are still sold as dietary supplements in the U.K., rather than as licensed drugs, as in other European countries. Monographs on herbal preparations are published in the U.K. by the British Herbal Medicine Association (BHMA). The 1996 British Herbal Pharmacopoeia provides monographs for 169 herbs, including saw palmetto.
Saw palmetto was listed in the U.S. Pharmacopeia from 1900 to 1916, and the National Formulary from 1925 to 1942. At various times from 1938 to 1990 Food and Drug Acts and Amendments were passed to address the problems of drug safety and effectiveness. Beginning in 1972, the FDA began evaluating over-the-counter drugs, including herbal preparations. In the U.S., however, it is permissible to sell herbal products only if no claims or statements regarding their value in the prevention or treatment of disease are made. In the 1994 Dietary Supplement Health and Education Act (DSHEA), Congress exempted xe2x80x9cdietary supplementsxe2x80x9d including herbal preparations from FDA regulations. The FDA continues to evaluate health claims for herbal preparations, and will approve those claims it considers truthful. For saw palmetto, a frequently-used label in the U.S. includes the claim: xe2x80x9cHelps to maintain normal prostate functionxe2x80x9d.
Turning now to the process of extraction, as the saw palmetto berries are harvested, they are usually put into standard citrus boxes, which are then loaded onto flatbed trailers, and transported by truck to drying facilities. The ripe berries contain approximately 66% water and will keep for only a few days without spoiling. The berries are, therefore, dried for several days at about 130xc2x0-140xc2x0 F., and after drying may be stored for several years without deteriorating.
Dried berries are generally bagged and shipped to processing facilities where they are ground into a powder. About 10% of the total powder produced is placed into capsules, generally 500 mg or so, and sold as powdered whole berries. The bulk of the remaining powder is further processed, primarily by chemical extraction facilities in Europe, into a liquid extract which is sold in bulk to companies who fabricate soft gel capsules, also called gelts, for sale to the consumer.
Saw palmetto extract is sold alone (generally in 160 mg. soft gelts), and in a variety of herbal formulations for the treatment of male urological disorders, particularly benign prostatic hyperplasia (BPH) or enlargement of the prostate. As noted, saw palmetto extract is regulated as a prescription drug in Germany, and is used by many patients for treatment of BPH. In the United States, however, partly because of the FDA""s lack of regulatory oversight of herbal remedies, these products are used as dietary supplements which may also provide some health benefits. Such dietary supplements, including vitamins and minerals, are viewed by the Food and Nutrition Board of the U.S. Institute of Medicine defines as functional food products with a proven relationship to health maintenance.
As described above, the presently available saw palmetto products are either dried, powdered whole berries, or extracts obtained by extraction with organic solvents such as ethanol or hexane. These processes do not provide a high yield of the lipids which are the preferred components of a saw palmetto herbal product. In addition, the old processes do not allow for the formulation of a saw palmetto extract comprising a predetermined blend of the various lipid fractions, to thereby allow custom formulations to meet customer specifications.
With the foregoing in mind, the present invention advantageously provides a composition comprising an extract of saw palmetto berries, a method for making the extract, and a method of nutritional supplementation using the composition of the invention.
The composition is primarily intended for oral administration, generally as a gel capsule containing a unit dose. The preferred unit dose contains at least about 160 mg of saw palmetto lipids, and a most preferred unit dose contains about 320 mg of saw palmetto lipids. In addition, in a preferred embodiment of the invention the saw palmetto composition comprises a predetermined blend of saw palmetto phytosterols, saw palmetto triglycerides, and saw palmetto fatty acids, so that a custom blended product may be produced.
The invention also includes a method of extracting saw palmetto berries, wherein the berries are first dried, then ground substantially to a powder, followed by extraction of the ground berries with CO2 under relatively high pressure, and finally separating the extracted compounds from the CO2.
Extracting is accomplished by flowing supercritical CO2 through the powdered saw palmetto berries at an extraction pressure of at least about 500 bar. Those skilled in the art will recognize that a xe2x80x9cbarxe2x80x9d is a unit of pressure substantially equivalent to one atmosphere, or 105 newton/m2. Temperature during extraction is maintained at less than about 80xc2x0 C. Following extraction, the saw palmetto compounds are separated from the carbon dioxide by decreasing the pressure to a predetermined separation pressure lower than the extraction pressure, and at a temperature sufficient to prevent the carbon dioxide from solidifying. As the pressure is decreased, the dissolving power of the CO2 also decreases and the extracted components come out of solution and are deposited in the separation vessel. Extracting and separating may best be conducted under a substantially continuous flow of carbon dioxide.